Bridged silicone resin, film, electronic device and related methods

ABSTRACT

A bridged silicone resin is disclosed which has the general formula (1): (HSiO 3/2 ) x (SiO 3/2 —X—SiO 3/2 ) y (1); wherein x and y are each from &gt;0 to &lt;1 such that x+y=1; and wherein X is divalent group comprising a silarylene group or a —(CH 2 ) q SiRR 1 [O(SiRR 1 O) n ]SiRR 1 —(CH 2 ) q — group, where n is an integer from 1 to 10, each R and R 1  is an independently selected substituted or unsubstituted hydrocarbyl group, and q and q′ are each independently integers selected from 0 or from 1 to 6. Various methods relating to the bridged silicone resin and end uses thereof are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and all advantages of U.S.Provisional Patent Application No. 62/402,282 filed on Sep. 30, 2016,the content of which is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention generally relates to a silicone resin and, morespecifically, to a bridged silicone resin which forms films havingexcellent physical properties and to related methods, films, andelectronic devices.

DESCRIPTION OF THE RELATED ART

Silicone resins are known in the art and utilized in various end useapplications. Silicone resins typically include three-dimensionalnetworks attributable to the presence of T siloxy units (R⁰SiO_(3/2))and/or Q siloxy units (SiO_(4/2)), where R⁰ is a substituent. Propertiesof silicone resins differ depending on, among other things, theircross-link densities and molar fractions of siloxy units. Increasing thecross-link density generally results in a silicone resin having greaterhardness and/or rigidity. Silica, or glass, comprises Q siloxy units.

T resins, or silsesquioxanes, are often utilized for spin-on-glass (SOG)applications, whereby the T resins are applied on a substrate, spun intoa layer, and annealed to give spin-on-glass (SOG) films. SOG films aredesirable in that they may be formed from T resins in liquid form, e.g.in a solvent, and subsequently annealed to give the SOG films havingproperties similar to glass. Dielectric properties of the SOG filmsallows for many end use applications, particularly in the electronicsindustry.

However, unlike glass, SOG films are often brittle and suffer fromcracking at elevated temperatures. This may be particularly problematicat certain SOG film thicknesses. Thus, thermal stability and resistanceto cracking limits potential end use applications of SOG films and the Tresins suitable for preparing such SOG films.

SUMMARY OF THE INVENTION

The present invention provides a bridged silicone resin. The bridgedsilicone resin has the general formula (1):

(HSiO_(3/2))_(x)(SiO_(3/2)—X—SiO_(3/2))_(y)  (1);

wherein x and y are each from >0 to <1 such that x+y=1; and wherein X isdivalent group comprising a silarylene group or a—(CH₂)_(q)SiRR¹[O(SiRR¹O)_(n)]SiRR¹—(CH₂)_(q)— group, where n is aninteger from 1 to 10, each R and R¹ is an independently selectedsubstituted or unsubstituted hydrocarbyl group, and q and q′ are eachindependently integers selected from 0 or from 1 to 6.

A method of preparing the bridged silicone resin is also disclosed. Thismethod comprises reacting an initial silicone resin and a bridgingcompound to give the bridged silicone resin. The initial silicone resinhas the general formula (HSiO_(3/2))_(n); where n′ is 1. The bridgingcompound has the general formula (4):

R³—Z′—R³   (4);

wherein each R³ independently is a functional group reactive with thesilicon-bonded hydrogen atoms of the initial silicone resin, and Z′comprises an arylene group or a siloxane moiety.

The present invention also provides a method of forming a film with thebridged silicone resin. This method comprises applying the bridgedsilicone resin to a substrate. This method further comprises forming thefilm from the bridged silicone resin on the substrate. The film formedin accordance with this method is further provided by the presentinvention.

In addition, the present invention provides an electronic device. Theelectronic device comprises an electronic component, and the film formedfrom the bridged silicone resin disposed adjacent the electroniccomponent.

Finally, the present invention provides a method of insulating theelectronic device. This method comprises powering the electronic devicesuch that the electronic component has an elevated temperature of fromgreater than 20° C. to 1,000° C. The film insulates the electroniccomponent and exhibits substantial resistance to cracking at theelevated temperature.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a bridged silicone resin and a method ofpreparing the bridged silicone resin. The bridged silicone resin hasexcellent properties and is suited for numerous end-use applications.For example, the bridged silicone resin forms a film having excellentproperties, including dielectric properties, substantial crackresistance at elevated temperatures and thermal stability. Thus, thepresent invention also provides a method of forming a film with thebridged silicone resin and the film formed thereby. In view of theexcellent physical properties of the film, an electronic device and amethod of insulating the electronic device are further provided.However, end-use applications of the bridged silicone resin are notlimited to films or electronic devices. For example, the bridgedsilicone resin may be utilized as a component in a composition (e.g. anadhesive, a cosmetic, etc.), may be utilized to form articles other thanfilms, etc.

The bridged silicone resin has the general formula (1):

(HSiO_(3/2))_(x)(SiO_(3/2)—X—SiO_(3/2))_(y)  (1);

wherein x and y are each from >0 to <1 such that x+y=1; and wherein X isdivalent group comprising a silarylene group, or a—(CH₂)_(q)SiRR¹[O(SiRR¹)_(n)]SiRR¹—(CH₂)_(q′)— group, where n is aninteger from 1 to 10, each R and R¹ is an independently selectedsubstituted or unsubstituted hydrocarbyl group, and q and q′ are eachindependently integers selected from 0 or from 1 to 6.

Subscripts x and y are mole fractions and are independently selectedfrom >0 to <1 such that the x+y=1. In certain embodiments, x is from 0.5to <1, alternatively from 0.6 to <1, alternatively from 0.7 to <1,alternatively from 0.8 to <1. In these or other embodiments, y isfrom >0 to 0.5, alternatively from >0 to 0.4, alternatively from >0 to0.3, alternatively from >0 to 0.2. However, in other embodiments, y maybe greater than x such that the specific example ranges above areinverted.

X is divalent group. In a first embodiment, X comprises a silarylenegroup. The silarylene group may be any divalent group including at leastone silicon-bonded arylene group. In certain embodiments, the arylenegroup is bonded between two silicon atoms in X. Specific examples of X,including when X is the silarylene group, are below.

In a second embodiment, X is a —(CH₂)_(q)SiRR¹[O(SiRR¹O)_(n)]SiRR¹—(CH₂)_(q′)— group, where n is an integer from 1 to10, each R and R¹ is an independently selected substituted orunsubstituted hydrocarbyl group, and q and q′ are each independentlyintegers selected from 0 or from 1 to 6. In this second embodiment, Xmay be referred to as a divalent siloxane. In contrast, in the firstembodiment introduced above for X, X as the silarylene group typicallydoes not include siloxane (Si—O—Si) bonds.

Each R and each R¹ are independent selected and may be the same as ordifferent from one another. Any description herein relating to R alsoapplies independently to R¹ and vice versa. R and each R¹ mayindependently be linear, branched, and/or cyclic. Cyclic hydrocarbylgroups encompass aryl groups as well as saturated or non-conjugatedcyclic groups. Aryl groups may be monocyclic or polycyclic. Linear andbranched hydrocarbyl groups may independently be saturated orunsaturated. For example, linear hydrocarbyl groups include alkylgroups, alkenyl groups, alkynyl groups, etc. One example of acombination of a linear and cyclic hydrocarbyl group is an aralkylgroup. By “substituted,” it is meant that one or more hydrogen atoms maybe replaced with atoms other than hydrogen (e.g. a halogen atom, such aschlorine, fluorine, bromine, etc.), or a carbon atom within the chain ofR and/or R¹ may be replaced with an atom other than carbon, i.e., Rand/or R¹ may include one or more heteroatoms within the chain, such asoxygen, sulfur, nitrogen, etc.

Typically, the hydrocarbyl groups of each R and R¹ independentlycomprise alkyl or aryl groups. Alkyl groups typically have from 1 to 30carbon atoms, alternatively 1 to 24 carbon atoms, alternatively 1 to 20carbon atoms, alternatively 1 to 12 carbon atoms, alternatively 1 to 10carbon atoms, alternatively 1 to 6 carbon atoms, alternatively 1 to 4carbon atoms, alternatively 1 to 3 carbon atoms, alternatively 1 or 2carbon atoms, alternatively are methyl groups. Aryl groups typicallyhave from 5 to 9 carbon atoms, alternatively 6 to 7 carbon atoms, andalternatively 5 to 6 carbon atoms.

In the second embodiment of X above, the bridged silicone resin has thegeneral formula:

(HSiO_(3/2))_(x)(SiO_(3/2)—(CH₂)_(q)SiRR¹[O(SiRR¹O)_(n)]SiRR¹—(CH₂)_(q′)—SiO_(3/2))_(y),

where x, q, R, R¹, n, q′ and y are defined above. In certainembodiments, q and q′ are each 0. This is typically the case when thebridged silicone resin is prepared via a condensation reaction. In otherembodiments, q and q′ are each 2. This is typically the case when thebridged silicone resin is prepared via a hydrosilylation reaction. Inthe latter embodiments, each of q and q′ may independently be greaterthan 2, e.g. 6. 2 is typical for q and q′ when the hydrosilylationreaction involves silicon-bonded vinyl groups, which become the optionaldivalent groups indicated by q and q′, respectively. The hydrosilylationreaction may involve silicon-bonded groups other than vinyl groups, e.g.silicon-bonded hexenyl groups, in which case q and q′ are other than 2.

Although two embodiments of X are introduced above, the bridged siliconeresin may include siloxy units having different and independentlyselected divalent groups represented by X. Said differently, the bridgedsilicone resin may include combinations of the two embodimentsintroduced above.

In the first embodiment of X introduced above, X comprises thesilarylene group. One specific example of X comprising the silarylenegroup is below in general formula (2):

—(CH₂)_(q)—SiRR¹—X′—SiRR¹—(CH₂)_(q′)—  (2);

wherein q and q′ are each independently selected and defined above; Rand R¹ are independently selected and defined above; and X′ is adivalent linking group comprising an arylene group. In the embodiment ofgeneral formula (2), the arylene group (designated by X′) is bondeddirectly between two adjacent silicon atoms in the respective SiRR¹blocks. As such, X′ may be an arylene group itself such that generalformula (2) represents a silarylene group, or X′ may be a silarylenegroup such that X′ itself includes silicon atoms in addition to those inthe SiRR¹ blocks opposite X.

In general formula (2) above, the arylene group designated by X′ may beany arylene group. Typically, X′ is an arylene group such that X is asilarylene group, but X′ itself does not constitute a silarylene group.In these embodiments, X still comprises a silarylene group, but X′merely comprises an arylene group. Alternatively, X′ and X may eachcomprise a silarylene group.

When X′ comprises the arylene group (but not the silarylene group), onespecific example of X′ is set forth in general formula (3):

wherein p is an integer selected from 0 or from 1 to 3, r is 0 or 1, kand each k′ are independently integers selected from 0 or from 1 to 4, Yand each Y′ are independently selected from N, O, and 5, and each Z isindependently selected from 0, 5, SiR² ₂, CO, CR² ₂, SO₂, PO₂ and NR²,where each R² is independently H or a substituted or unsubstitutedhydrocarbyl group. Examples of substituted and unsubstituted hydrocarbylgroups are set forth above with respect to R and R¹.

In the embodiment of X′ above, Y and Y′, which are indicated by k andk′, respectively, are optional heteroatoms that may be part of therespective aromatic structures in general formula (3). Typically, k andk′ are each 0 such that the optional heteroatoms represented by Y andY′, respectively, are absent.

Z, indicated by subscript r, is an optional heteroatom or moiety presentbetween adjacent aromatic structures. Subscript r is independentlyselected such that when the block indicated by subscript p is greaterthan 0, each repeating block may or may not include Z, and Z isindependently selected in any instance in which it is present.

When r is 0, p is 0, and k′ is 0, X′ has the general formula —(C₆H₄)—.In this specific embodiment, X has the general formula—(CH₂)_(q)—SiRR¹—(C₆H₄)—SiRR¹—(CH₂)_(q′)—, where q, R, R¹, q′ aredefined above. In certain embodiments, q and q′ are each 2. X′, or—(C₆H₄)—, is bonded between silicon atoms. These bonds may be at anylocation of —(C₆H₄)—, i.e., at the ortho, meta, and/or para location.

In other embodiments, r is 0 and p is 1. When k and k′ are each 0, X′has in this embodiment the general formula: —(C₆H₄)—(C₆H₄)—, and X hasthe general formula —(CH₂)_(q)—SiRR¹—(C₆H₄)—(C₆H₄)—SiRR¹—(CH₂)_(q′)—,where q, R, R¹, q′ are defined above. In certain embodiments, q and q′are each 2. X′, or —(C₆H₄)—(C₆H₄)—, is bonded between silicon atoms.These bonds may be at any location of each —(C₆H₄)—, i.e., at the ortho,meta, and/or para location.

In yet other embodiments, r is 1 and p is 1. When k and k′_(are each 0), X′ may have, for example, any of the structures belowdepending on a selection of Z:

R² is defined above and independently is H or a substituted orunsubstituted hydrocarbyl group. These are merely exemplary examples ofsuitable species for X′.

For the specific examples provided above for X′, X has the followingcorresponding structures (presented in the order in which exemplaryexamples of X′ are introduced above):

Alternatively still, in other embodiments, r is 1 and p is >1, i.e., pis 2 or 3. In these embodiments, Z may independently be present orabsent from each block indicated by p, and may be independently selectedif present in two or more blocks indicated by p.

In various embodiments, the bridged silicone resin has a weight averagemolecular weight (M_(W)) of from 100 to 5,000, alternatively from 115 to4,000; alternatively from 130 to 1,000, as measured by gel permeationchromatography techniques (GPC) calibrated based on polystyrenestandards.

As introduced above, a method of preparing the bridged silicone resin isalso disclosed (the “preparation method”). The preparation methodcomprises reacting an initial silicone resin and a bridging compound togive the bridged silicone resin.

The initial silicone resin has the general formula (HSiO_(3/2))_(n′),where n′ is 1. The initial silicone resin is a hydrogen silsesquioxaneresin (HSQ), which is a resin comprising, alternatively consistingessentially of, alternatively consisting of, T siloxy units. Hydrogensilsesquioxane resins, and methods of their preparation, are known inthe art.

Typically, the initial silicone resin typically has a weight averagemolecular weight (M_(W)) of from 1,500 to 100,000, alternatively from2,000 to 50,000, alternatively from 3,000 to 30,000, as measured by gelpermeation chromatography techniques (GPC) calibrated based onpolystyrene standards.

The initial silicone resin may be disposed in a vehicle, alternatively asolvent, when preparing the bridged silicone resin. The vehicle may beany vehicle for carrying the initial silicone resin, alternatively atleast partially solubilizing the initial silicone resin, alternativelysolubilizing the initial silicone resin.

Examples of suitable vehicles include, but are not limited to, saturatedaliphatic hydrocarbons such as n-pentane, hexane, n-heptane, isooctaneand dodecane; cycloaliphatic hydrocarbons such as cyclopentane andcyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene andmesitylene; cyclic ethers such as tetrahydrofuran (THF) and dioxane;alcohols such as methanol, ethanol, isopropanol, butanol, or n-propanol;ketones such as methyl isobutyl ketone (MIBK); glycol ethers such aspropylene glycol methyl ether, dipropylene glycol methyl ether,propylene glycol n-butyl ether, propylene glycol n-propyl ether,propylene glycol methyl ether acetate (PGMEA), or ethylene glycoln-butyl ether; halogenated alkanes such as trichloroethane,dichloromethane, 1,1,1-trichloroethane, methylene chloride orchloroform; dimethyl sulfoxide; dimethyl formamide; acetonitrile; whitespirits; mineral spirits; naphtha; and halogenated aromatic hydrocarbonssuch as bromobenzene and chlorobenzene. Combinations of differentvehicles may also be utilized.

When the initial silicone resin is disposed in the vehicle, the relativeamounts of the vehicle and the initial silicone resin may vary.Typically, the relative amounts are chosen based on a desired viscosityor flowability of a mixture of the initial silicone resin and thevehicle. In certain embodiments, the mixture comprises the initialsilicone resin in an amount of from greater than 0 to 50, alternativelyfrom 2.5 to 47.5, alternatively from 5 to 42.5, alternatively from 7.5to 40, alternatively from 10 to 30, weight percent based on the totalweight of the mixture. In these embodiments, the balance of the mixturetypically is the vehicle.

In certain embodiments, the bridging compound has the general formula(4):

R³—Z′—R³  (4);

wherein each R³ independently is a functional group reactive with thesilicon-bonded hydrogen atoms of the initial silicone resin, and Z′comprises an arylene group or a siloxane moiety. Typically, each R³ issilicon-bonded in the bridging component, i.e., Z′ includes siliconatoms to which each R³ is bonded. The bridging compound forms X in thebridged silicone resin after reacting with the initial silicone resin.

The relative amounts of the initial silicone resin and the bridgingcompound depends on the selection of these components and the desiredratio of silicon-bonded hydrogen atoms in the initial silicone resin toR³ functional groups in the bridging compound, as well as the desiredstructure of the bridged silicone resin. The molar ratio ofsilicon-bonded hydrogen atoms in the initial silicone resin to R³functional groups in the bridging compound may range, for example, from40:1 to 1:1, alternatively from 20:1 to 2:1, alternatively from 10:1 to5:1.

In specific embodiments, Z′ has the general formula (5):

—SiRR¹—X′—SiRR¹—(5);

wherein each R and R¹ is independently selected and defined above, andX′ is defined above.

R³ is reactive with the silicon-bonded hydrogen atoms of the initialsilicone resin. In certain embodiments, R³ includes an ethylenicallyunsaturated group. The unsaturated group is typically terminal in R³. Insuch embodiments, R³ may independently be an alkenyl group and/or analkynyl group. When R³ includes the ethylenically unsaturated group, thereaction between the bridging compound and the initial silicone resin isa hydrosilylation reaction.

When each R³ of the bridging compound is a vinyl group, and when Z′comprises the arylene group, exemplary examples of suitable bridgingcompounds which generally correspond to the exemplary examples of Xabove for the bridged silicone resin are below (in the same order aspresented above):

where R and R¹ are defined above.

In the exemplary examples above, each R³ is silicon-bonded vinyl. Inthese exemplary examples, Z′ of the bridging compound comprises as thearylene compound a silarylene compound, as in general formula (5) above.However, general formula could be represented different with the siliconatoms attributable to each R³ and not to Z′ such that Z′ is an arylenecompound and each R³ is, in these specific embodiments, —SiRR¹—CH═CH₂.Moreover, the arylene groups above could be replaced with siloxanemoieties, and/or the vinyl groups above could be replaced with hydroxylgroups.

When X of the bridged silicone resin is—(CH₂)_(q)SiRR¹[O(SiRR¹O)_(n)]SiRR¹—(CH₂)_(q′)—, one specific example ofthe bridged compound when q and q′ are each 2 isCH₂═CH—SiRR¹[O(SiRR¹O)_(n)]SiRR¹—CH═CH₂, with n being defined above.This corresponds to q and q′ each being 2. In this embodiment, R³ isagain silicon-bonded vinyl, and Z′ is the siloxane moiety, in this case,SiRR¹[O(SiRR¹O)_(n)]SiRR¹.

The hydrosilylation reaction between the bridging compound and theinitial silicone resin typically takes place in the presence of ahydrosilylation catalyst, which can be any of the well-knownhydrosilylation catalysts comprising a platinum group metal or acompound containing a platinum group metal.

By platinum group metal it is meant ruthenium, rhodium, palladium,osmium, iridium and platinum as well as any complexes thereof.Typically, the platinum group metal is platinum, based on its highactivity in hydrosilylation reactions. Platinum group metal-containingcatalysts useful for the hydrosilylation catalyst include the platinumcomplexes prepared as described by Willing, U.S. Pat. No. 3,419,593, andBrown et al, U.S. Pat. No. 5,175,325, each of which is herebyincorporated by reference to show such complexes and their preparation.Other examples of useful platinum group metal-containing catalysts canbe found in Lee et al., U.S. Pat. No. 3,989,668; Chang et al., U.S. Pat.No. 5,036,117; Ashby, U.S. Pat. No. 3,159,601; Larnoreaux, U.S. Pat. No.3,220,972; Chalk et al., U.S. Pat. No. 3,296,291; Modic, U.S. Pat. No.3,516,946; Karstedt, U.S. Pat. No. 3,814,730; and Chandra et al., U.S.Pat. No. 3,928,629 all of which are hereby incorporated by reference toshow useful platinum group metal-containing catalysts and methods fortheir preparation. The platinum group-containing catalyst can beplatinum group metal, platinum group metal deposited on a carrier suchas silica gel or powdered charcoal, or a compound or complex of aplatinum group metal. Specific examples of platinum-containing catalystsinclude chloroplatinic acid, either in hexahydrate form or anhydrousform, and or a platinum-containing catalyst which is obtained by amethod comprising reacting chloroplatinic acid with an aliphaticallyunsaturated organosilicon compound such as divinyltetramethyldisiloxane,or alkene-platinum-silyl complexes as described in Roy, U.S. Pat. No.6,605,734. These alkene-platinum-silyl complexes may be prepared, forexample by mixing 0.015 mole (COD)PtCl₂ with 0.045 mole COD and 0.0612moles HMeSiCl₂.

The hydrosilylation catalyst can also be a supported hydrosilylationcatalyst comprising a solid support having a platinum group metal on thesurface thereof. Examples of supported catalysts include, but are notlimited to, platinum on carbon, palladium on carbon, ruthenium oncarbon, rhodium on carbon, platinum on silica, palladium on silica,platinum on alumina, palladium on alumina, and ruthenium on alumina.

The hydrosilylation catalyst may also or alternatively be aphotoactivatable hydrosilylation catalyst, which may initiate curing viairradiation and/or heat. The photoactivatable hydrosilylation catalystcan be any hydrosilylation catalyst capable of catalyzing thehydrosilylation reaction, particularly upon exposure to radiation havinga wavelength of from 150 to 800 nanometers (nm). The photoactivatablehydrosilylation catalyst can be any of the well-known hydrosilylationcatalysts comprising a platinum group metal or a compound containing aplatinum group metal. The platinum group metals include platinum,rhodium, ruthenium, palladium, osmium, and iridium. Typically, theplatinum group metal is platinum, based on its high activity inhydrosilylation reactions. The suitability of particularphotoactivatable hydrosilylation catalysts for use in the composition ofthe present invention can be readily determined by routineexperimentation.

Specific examples of photoactivatable hydrosilylation catalysts suitablefor purposes of the present invention include, but are not limited to,platinum(II) β-diketonate complexes such as platinum(II)bis(2,4-pentanedioate), platinum(II) bis(2,4-hexanedioate), platinum(II)bis(2,4-heptanedioate), platinum(II) bis(1-phenyl-1,3-butanedioate,platinum(II) bis(1,3-diphenyl-1,3-propanedioate), platinum(II)bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedioate);(η-cyclopentadienyl)trialkylplatinum complexes, such as(Cp)trimethylplatinum, (Cp)ethyldimethylplatinum, (Cp)triethylplatinum,(chloro-Cp)trimethylplatinum, and (trimethylsilyl-Cp)trimethylplatinum,where Cp represents cyclopentadienyl; triazene oxide-transition metalcomplexes, such as Pt[C₆H₅NNNOCH₃]₄, Pt[p-CN—C₆H₄NNNOC₆H₁₁]₄,Pt[p-H₃COC₆H₄NNNOC₆H₁₁]₄, Pt[p-CH₃(CH₂)_(x)—C₆H₄NNNOCH₃]₄,1,5-cyclooctadiene.Pt[p-CN—C₆H₄NNNOC₆H₁₁]₂,1,5-cyclooctadiene.Pt[p-CH₃O—C₆H₄NNNOCH₃]₂,[(C₆H₅)₃P]₃Rh[p-CN—C₆H₄NNNOC₆H₁₁], and Pd[p-CH (CH₂)_(x)—C₆H₄NNNOCH₃]₂,where x is 1, 3, 5, 11, or 17; (η-diolefin)(σ-aryl)platinum complexes,such as (η⁴-1,5-cyclooctadienyl)diphenylplatinum,η⁴-1,3,5,7-cyclooctatetraenyl)diphenylplatinum,(η⁴-2,5-norboradienyl)diphenylplatinum,(η⁴-1,5-cyclooctadienyl)bis-(4-dimethylaminophenyl)platinum,(η⁴-1,5-cyclooctadienyl)bis-(4-acetylphenyl)platinum, and(η⁴-1,5-cyclooctadienyl)bis-(4-trifluormethylphenyl)platinum. Typically,the photoactivatable hydrosilylation catalyst is a Pt(II) β-diketonatecomplex and more typically the catalyst is platinum(II)bis(2,4-pentanedioate). The hydrosilylation catalyst can be a singlephotoactivatable hydrosilylation catalyst or a mixture comprising two ormore different photoactivatable hydrosilylation catalysts.

The concentration of the hydrosilylation catalyst is sufficient tocatalyze the hydrosilylation reaction between the bridging compound andthe initial silicone resin. The concentration of the hydrosilylationcatalyst typically provides from 0.1 to 1000 ppm of platinum groupmetal, alternatively from 0.5 to 100 ppm of platinum group metal,alternatively from 1 to 25 ppm of platinum group metal, based on thecombined weight of the bridging compound and the initial silicone resin.

In these or other embodiments, R³ includes a hydroxyl group,alternatively R³ is a hydroxyl group. In these embodiments, the reactionbetween the bridging compound and the initial silicone resin is acondensation reaction.

In these embodiments, R³ may initially be any hydrolysable group. Thehydrolysable groups may first undergo hydrolysis in the presence ofwater to give the hydroxyl group, which subsequently condenses with thesilicon-bonded hydrogen atoms of the initial silicone resin to give thebridged silicone resin (with water as a byproduct). In theseembodiments, the bridged compound may undergo hydrolysis and subsequentcondensation with the initial silicone resin.

Examples of hydrolysable groups when bonded to silicon include H, ahalide group, an alkoxy group, an alkylamino group, a carboxy group, analkyliminoxy group, an alkenyloxy, and an N-alkylamido group.

When X of the bridged silicone resin is—(CH₂)_(q)SiRR¹[O(SiRR¹O)_(n)]SiRR¹—(CH₂)_(q′)—, one specific example ofthe bridged compound is OH—SiRR¹[O(SiRR¹O)_(n)]SiRR¹—OH, with n beingdefined above. This corresponds to q and q′ each being 0. In thisembodiment, R³ is silicon-bonded hydroxyl, and Z′ is the siloxanemoiety, in this case, SiRR¹[O(SiRR¹O)_(n)]SiRR¹, where n is definedabove.

The condensation reaction between the bridging compound and the initialsilicone resin typically takes place in the presence of a catalyst,which can be any condensation catalyst.

Examples of suitable condensation catalyst include acids, such ascarboxylic acids, e.g. formic acid, acetic acid, propionic acid, butyricacid, and/or valeric acid; bases; metal salts of organic acids, such asdibutyl tin dioctoate, iron stearate, and/or lead octoate; titanateesters, such as tetraisopropyl titanate and/or tetrabutyl titanate;chelate compounds, such as acetylacetonato titanium; transition metalcatalysts, such as platinum-containing catalysts, including for exampleany of those introduced above as being suitable hydrosilylationcatalysts; aminopropyltriethoxysilane, and the like. If utilized, thecondensation catalyst are typically utilized in a catalytic amount, e.g.in amount of from greater than 0 to 5, alternatively 0.0001 to 1,alternatively 0.001 to 0.1, percent by weight, based on 100 parts byweight based on the combined weight of the bridging compound and theinitial silicone resin.

When R³ includes the ethylenically unsaturated group, subscripts q andq′ are each typically at least 2 in X of the bridged silicone resin.When R³ is a hydroxyl group, subscripts q and q′ are each typically 0 inX of the bridged silicone resin.

The reaction to give the bridged silicone resin may be carried out atambient conditions or at modified conditions. For example, the reactionmay be carried out at elevated temperatures (e.g. from greater thanambient to 100° C.), under stirring/shear, under vacuum, under an inertatmosphere, etc. The bridged silicone resin is typically formed in areaction mixture, and the preparation method may further compriseisolating the bridged silicone resin from the reaction mixture, e.g. byfiltration.

One of skill in the art readily understands how to prepare such bridgingcompounds. As but one example, when X is—(CH₂)₂—Si(CH₃)₂—(C₆H₄)—O—(C₆H₄)—Si(CH₃)₂—(CH₂)₂—, the bridging compoundmay be formed in accordance with the following reaction mechanism:

where Vi indicates a vinyl group and Me indicates a methyl group.

The initial silicone resin and the bridging compound may be reacted invarious amounts or ratios depending on desired end properties of thebridged silicone resin. In certain embodiments, the bridging compound isutilized in an amount of from greater than 0 to 30, alternatively fromgreater than 0 to 20, alternatively from greater than 0 to 15,alternatively from greater than 0 to 10, weight percent based on thecombined weight of the bridging compound and the initial silicone resin.

The present invention also provides a method of forming a film with thebridged silicone resin (“film preparation method”). The film preparationmethod comprises applying the bridged silicone resin to a substrate. Thefilm preparation method further comprises forming the film from thebridged silicone resin on the substrate. Forming the film with thebridged silicone resin encompasses merely applying the bridged siliconeresin on the substrate, drying, annealing, and whether or not there areany physical and/or chemical changes within the bridged silicone resinor the film.

In certain embodiments, applying the bridged silicone resin to thesubstrate comprises applying a silicone composition comprising thebridged silicone resin and a vehicle to the substrate. The vehicle maycarry, alternatively partially solubilize, alternatively fullysolubilize the bridged silicone resin. The vehicle generally reduces aviscosity of the silicone composition such that the silicone compositionmay be applied in wet form.

The vehicle may be any suitable vehicle. Examples of suitable vehiclesinclude, but are not limited to, saturated aliphatic hydrocarbons suchas n-pentane, hexane, n-heptane, isooctane and dodecane; cycloaliphatichydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbonssuch as benzene, toluene, xylene and mesitylene; cyclic ethers such astetrahydrofuran (THF) and dioxane; alcohols such as methanol, ethanol,isopropanol, butanol, or n-propanol; ketones such as methyl isobutylketone (MIBK); glycol ethers such as propylene glycol methyl ether,dipropylene glycol methyl ether, propylene glycol n-butyl ether,propylene glycol n-propyl ether, propylene glycol methyl ether acetate(PGMEA), or ethylene glycol n-butyl ether; halogenated alkanes such astrichloroethane, dichloromethane, 1,1,1-trichloroethane, methylenechloride or chloroform; dimethyl sulfoxide; dimethyl formamide;acetonitrile; white spirits; mineral spirits; naphtha; and halogenatedaromatic hydrocarbons such as bromobenzene and chlorobenzene.Combinations of vehicles may also be utilized.

The relative amount of the bridged silicone resin in the siliconecomposition may vary. In various embodiments, the silicone compositioncomprises the bridged silicone resin in an amount of from 5 to 75 wt %,alternatively from 10 to 60 wt %, alternatively from 15 to 55 wt %,alternatively from 20 to 50 wt %, alternatively from 10 to 30 wt %,alternatively from 30 to 50 wt %, alternatively 12±2 wt %, alternatively14±2 wt %, alternatively 16±2 wt %, alternatively 18±2 wt %,alternatively 20±2 wt %, alternatively 25±2 wt %, alternatively 30±2 wt%, alternatively 35±2 wt %, alternatively 40±2 wt %, alternatively 45±2wt %, alternatively 50±2 wt %, alternatively 55±2 wt %, alternatively60±2 wt %, alternatively 65±2 wt, all based on total weight of thesilicone composition.

Applying the bridged silicone resin (itself or in the siliconecomposition) may comprise any suitable application technique. Typically,the silicone composition is applied in wet form via a wet coatingtechnique. In certain embodiments, the bridged silicone resin is appliedby i) spin coating; ii) brush coating; iii) drop coating; iv) spraycoating; v) dip coating; vi) roll coating; vii) flow coating; viii) slotcoating; ix) gravure coating; or x) a combination of any of i) to ix).

In specific embodiments, the bridged silicone resin is applied by spincoating. In these embodiments, the silicone composition is dispensed ona substrate, such as a device wafer (e.g., a semiconductor device wafer,e.g., a gallium arsenide wafer, a silicon (Si) wafer, a silicon carbide(SiC) wafer, a Si wafer having a SiO_(x′) layer disposed thereon, or aSi wafer having a SiN layer disposed thereon) to give a wet deposit.Subscript x′ is a rational or irrational number expressing the averagenumber of oxygen atoms per one silicon atom in a silicon oxide layer.Typically, x′ is from 1 to 4.

The wet deposit and substrate are then spin coated for a period of timeto give a spinned layer. In spin-coating the wet deposit on thesubstrate, the spin-coating may be done at a maximum spin speed and fora spin time sufficient to obtain a desired thickness of the spinnedlayer. The maximum spin speed may be from 400 to 5,000, alternativelyfrom 500 to 4,000, alternatively from 800 to 3,000, revolutions perminute (rpm).

In spin-coating the wet deposit on the wafer, the spin time may be from0.5 seconds to 10 minutes. The spin time may be fixed, e.g., keptconstant at from 30 seconds to 2 minutes, and a person of ordinary skillin the art using a conventional spin-coater apparatus may then readilyadjust the spin speed to obtain a particular thickness.

In certain embodiments, the film preparation method further comprisesannealing the spinned layer to form the film on the substrate. When thespinned layer is annealed, the film may be referred to as aspin-on-glass (SOG) layer or film. The spinned layer is typically wet.As such, the spinned layer may be heated prior to annealing, e.g. todrive any vehicle from the spinned layer prior to annealing the bridgedsilicone resin of the spinned layer to give the film.

Typically, the substrate has an integrated hot plate or an integrated orstand-alone furnace, which may be quartz-lined. The substrate andspinned layer are heated, e.g. over three hot plates in succession attemperatures of from 125 to 175° C., e.g. 150° C.; then from 175 to 225°C., e.g. 200° C.; and then from 325 to 375° C., e.g. 350° C., each for aperiod of time. The period of time may be from greater than 0 seconds to10 minutes, alternatively about one minute. The heating step drives anyvehicle from the silicone composition separate from the bridged siliconeresin to give a dried film. The heating step also begins to initiatestructural changes within the bridged silicone resin prior to finalannealing. Ambient moisture and water may contribute to furtherhydrolysis and/or condensation of T units within the bridged siliconeresin to give Q units. In certain embodiments, after the heating stepsdescribed above, the dried film may be exposed to ambient conditions andrelative humidity.

The dried film then typically undergoes annealing at a temperature offrom about 300 to 900, alternatively from 350 to 500, alternatively from375 to 425° C. Generally, annealing takes place in an inert environment,e.g. under nitrogen. The Si—H bond dissociation due to oxidationtypically occurs at temperatures greater than 360° C. However, at leastsome Si—H bonds generally remain even after annealing.

The film may be bonded to the substrate (physically and/or chemically)or the film may be peelable or otherwise removable from the substrate.The film may be physical bonded to the substrate and/or chemicallybonded to the substrate.

In various embodiments, the film is subjected to further processingdepending upon its end use application. For example, the film may besubjected to oxide deposition (e.g. SiO₂ deposition), resist depositionand patterning, etching, chemical or plasma stripping, metallization, ormetal deposition. Such further processing techniques are generallyknown. Such deposition may be chemical vapor deposition (includinglow-pressure chemical vapor deposition, plasma-enhanced chemical vapordeposition, and plasma-assisted chemical vapor deposition), physicalvapor deposition, or other vacuum deposition techniques. Many suchfurther processing techniques involve elevated temperatures,particularly vacuum deposition, for which the film is well suited inview of its excellent thermal stability.

The film has a thickness that may vary depending upon its end useapplication. Typically, the film has a thickness of from greater than 0to 10 micrometers (pm), alternatively from 1.5 to 10 micrometers (μm).However, other thicknesses are contemplated, e.g. from 0.1 to 200 μm.For example, the thickness of the film may be from 0.2 to 175 μm;alternatively from 0.5 to 150 μm; alternatively from 0.75 to 100 μm;alternatively from 1 to 75 μm; alternatively from 2 to 60 μm;alternatively from 3 to 50 μm; alternatively from 4 to 40 μm;alternatively any one of 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30,35, 40, 45, 50, 60, 70, 75, 80, 90, 100, 150, 175, and 200 μm.

The film has excellent physical properties, particularly as compared toconventional spin-on-glass (SOG) films. For example, many conventionalSOG films are brittle with poor thermal stability. However, theinventive film has substantial resistance to cracking and excellentthermal stability at elevated temperatures. For example, in certainembodiments, the film substantially resists cracking when heated to anelevated temperature of i) from 100 to 1000° C.; ii) from 400 to 850°C.; or iii) both i) and ii).

Substantial resistance to cracking, as used herein, means that whenvisually inspected under an optical and/or scanning electronicmicroscope, the films do not exhibit cracking at a thickness of 1.5micrometers (μm) when heated at 500° C. for 60 minutes under nitrogen.

The film also has excellent thermal stability as well as etchselectivity for patterning (if the film undergoes further processing asintroduced above).

The present invention also provides an electronic device. The electronicdevice comprises an electronic component, and the film disposed adjacentthe electronic component. By “adjacent,” it is meant that the film isdisposed adjacent and in contact with, alternatively adjacent butseparated from, the electronic component. The substrate on which thefilm is formed may be the electronic component of the electronic device.

The electronic device is not limited and may be referred to as a“microelectronic device” and/or an “electronic circuit.” Exemplaryexamples thereof include silicon based devices, gallium arsenidedevices, focal plane arrays, opto-electronic devices, photovoltaiccells, optical devices, dielectric layers, doped dielectric layers toproduce transistor-like devices, pigment loaded binder systemscontaining silicon to produce capacitors and capacitor-like devices,multilayer devices, 3-D devices, silicon-on-insulator (SOI) devices,super lattice devices and the like.

The electrical component of the electronic device is typically asemiconducting component, alternatively a conducting component. The filmhas excellent dielectric properties and may insulate such semiconductingcomponents from heat and/or electric current. However, the electricalcomponent may be any component of the electrical device, which are wellknown. The heat may be attributable to an environment or ambientconditions in which the electrical device is utilized. Alternatively,the heat may be attributable to use and powering of the electronicdevice, which generally results in the generation of heat at least invarious electrical components of the electrical device, particularlyelectrically conductive components thereof.

A method of insulating the electronic device is also provided. Themethod comprises powering the electronic device such that the electroniccomponent has an elevated temperature of from greater than 20° C. to1,000° C. The film insulates the electronic component and exhibitssubstantial resistance to cracking at the elevated temperature asdescribed above. Because of the excellent dielectric properties of thefilm, insulation typically extends to insulation from heat at theelevated temperature and to insulation from electrical current whenpowering the electronic device.

Embodiment 1 relates to a bridged silicone resin having the generalformula (1):

(HSiO_(3/2))_(x)(SiO_(3/2)—X—SiO_(3/2))_(y)  (1);

wherein x and y are each from >0 to <1 such that x+y=1; and wherein X isdivalent group comprising a silarylene group, or a—(CH₂)_(q)SiRR¹[O(SiRR¹O)_(n)]SiRR¹—(CH₂)_(q′)— group, where n is aninteger from 1 to 10, each R and R¹ is an independently selectedsubstituted or unsubstituted hydrocarbyl group, and q and q′ are eachindependently integers selected from 0 or from 1 to 6.

Embodiment 2 relates to the bridged silicone resin of Embodiment 1,wherein X has the general formula (2):

—(CH₂)_(q)—SiRR¹—X′—SiRR¹—(CH₂)_(q′)—  (2);

wherein q and q′ are each independently selected and defined above; Rand R¹ are independently selected and defined above; and X′ is adivalent linking group comprising an arylene group.

Embodiment 3 relates to the bridged silicone resin of Embodiment 2,wherein X′ has the general formula (3):

wherein p is an integer selected from 0 or from 1 to 3, r is 0 or 1, kand each k′ are independently integers selected from 0 or from 1 to 4, Yand each Y′ are independently selected from N, O, and S, and each Z isindependently selected from O, S, SiR² ₂, CO, CR² ₂, SO₂, PO₂ and NR²,where each R² is independently H or a substituted or unsubstitutedhydrocarbyl group.

Embodiment 4 relates to a method of preparing the bridged silicone resinof Embodiment 1. The method of Embodiment 4 comprises reacting aninitial silicone resin and a bridging compound to give the bridgedsilicone resin;

wherein the initial silicone resin has the general formula(HSiO_(3/2))_(n′), where n′ is 1; and

wherein the bridging compound has the general formula (4):

R³—Z′—R³   (4);

wherein each R³ independently is a functional group reactive with thesilicon-bonded hydrogen atoms of the initial silicone resin, and Z′comprises an arylene group or a siloxane moiety.

Embodiment 5 relates to the method of Embodiment 4, wherein Z′ has thegeneral formula (5):

—SiRR¹—X′—SiRR¹—  (5);

wherein each R and R¹ is independently selected and defined above; and

X′ is a divalent linking group having the general formula (3):

wherein p is an integer selected from 0 or from 1 to 3, r is 0 or 1, kand each k′ are independently integers selected from 0 or from 1 to 4, Yand each Y′ are independently selected from N, 0, and S, and each Z isindependently selected from O, S, SiR² ₂, CO, CR² ₂, SO₂, PO₂ and NR²,where each R² is independently H or a substituted or unsubstitutedhydrocarbyl group.

Embodiment 6 relates to the method of Embodiments 4 or 5, whereinreacting the initial silicone resin and the bridging compound comprises(i) a hydrosilylation reaction; (ii) a condensation reaction; or (iii) acombination of (i) and (ii).

Embodiment 7 relates to the method of any one of Embodiments 4-6,wherein the initial silicone resin and the bridging compound are reactedin the presence of a catalyst.

Embodiment 8 relates to a method of forming a film with a bridgedsilicone resin. The method of Embodiment 8 comprises:

applying the bridged silicone resin to a substrate; and

forming the film from the bridged silicone resin on the substrate;

wherein the bridged silicone resin is the bridged silicone resin of anyone of Embodiments 1-3.

Embodiment 9 relates to the method of Embodiment 8, wherein applying thebridged silicone resin comprises applying a silicone compositioncomprising the bridged silicone resin and a vehicle.

Embodiment 10 relates to the method of Embodiments 8 or 9, wherein thebridged silicone resin is applied by i) spin coating; ii) brush coating;iii) drop coating; iv) spray coating; v) dip coating; vi) roll coating;vii) flow coating; viii) slot coating; ix) gravure coating; or x) acombination of any of i) to ix).

Embodiment 11 relates to the method of Embodiment 9, further comprising

spinning the silicone composition on the substrate to form a spinnedlayer on the substrate; and

annealing the spinned layer to form the film on the substrate.

Embodiment 12 relates to a film formed in accordance with the method ofany of Embodiments 8-11.

Embodiment 13 relates to the film of Embodiment 12 having a thickness offrom greater than 0 to 10 microns.

Embodiment 14 relates to the film of Embodiments 12 or 13, whichsubstantially resists cracking when heated to a temperature of i) from100 to 1000° C.; ii) from 400 to 850° C.; or iii) both i) and ii).

Embodiment 15 relates to an electronic device, comprising:

an electronic component; and

a film disposed adjacent the electronic component;

wherein the film is the film of any one of Embodiments 12-14.

Embodiment 16 relates to use of the electronic device of Embodiment 15.

Embodiment 17 relates to a method of insulating an electronic devicewhich comprises an electronic component and a film disposed adjacent theelectronic component. The method of Embodiment 17 comprises:

powering the electronic device such that the electronic component has anelevated temperature of from greater than 20° C. to 1,000° C.;

wherein the film is the film of any one of Embodiments 12-14;

wherein the film insulates the electronic component and exhibitssubstantial resistance to cracking at the elevated temperature.

The electrical component of the electronic device is typically asemiconducting component, alternatively a conducting component. The filmhas excellent dielectric properties and may insulate such semiconductingcomponents from heat and/or electric current. However, the electricalcomponent may be any component of the electrical device, which are wellknown. The heat may be attributable to an environment or ambientconditions in which the electrical device is utilized. Alternatively,the heat may be attributable to use and powering of the electronicdevice, which generally results in the generation of heat at least invarious electrical components of the electrical device, particularlyelectrically conductive components thereof.

A method of insulating the electronic device is also provided. Themethod comprises powering the electronic device such that the electroniccomponent has an elevated temperature of from greater than 20° to 1,000°C. The film insulates the electronic component and exhibits substantialresistance to cracking at the elevated temperature as described above.Because of the excellent dielectric properties of the film, insulationtypically extends to both insulation from heat at the elevatedtemperature and to insulation from electrical current when powering theelectronic device.

It is to be understood that the appended claims are not limited toexpress and particular compounds, compositions, or methods described inthe detailed description, which may vary between particular embodimentswhich fall within the scope of the appended claims. With respect to anyMarkush groups relied upon herein for describing particular features oraspects of various embodiments, different, special, and/or unexpectedresults may be obtained from each member of the respective Markush groupindependent from all other Markush members. Each member of a Markushgroup may be relied upon individually and or in combination and providesadequate support for specific embodiments within the scope of theappended claims.

Further, any ranges and subranges relied upon in describing variousembodiments of the present invention independently and collectively fallwithin the scope of the appended claims, and are understood to describeand contemplate all ranges including whole and/or fractional valuestherein, even if such values are not expressly written herein. One ofskill in the art readily recognizes that the enumerated ranges andsubranges sufficiently describe and enable various embodiments of thepresent invention, and such ranges and subranges may be furtherdelineated into relevant halves, thirds, quarters, fifths, and so on. Asjust one example, a range “of from 0.1 to 0.9” may be further delineatedinto a lower third, i.e., from 0.1 to 0.3, a middle third, i.e., from0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9, whichindividually and collectively are within the scope of the appendedclaims, and may be relied upon individually and/or collectively andprovide adequate support for specific embodiments within the scope ofthe appended claims. In addition, with respect to the language whichdefines or modifies a range, such as “at least,” “greater than,” “lessthan,” “no more than,” and the like, it is to be understood that suchlanguage includes subranges and/or an upper or lower limit. As anotherexample, a range of “at least 10” inherently includes a subrange of fromat least 10 to 35, a subrange of from at least 10 to 25, a subrange offrom 25 to 35, and so on, and each subrange may be relied uponindividually and/or collectively and provides adequate support forspecific embodiments within the scope of the appended claims. Finally,an individual number within a disclosed range may be relied upon andprovides adequate support for specific embodiments within the scope ofthe appended claims. For example, a range “of from 1 to 9” includesvarious individual integers, such as 3, as well as individual numbersincluding a decimal point (or fraction), such as 4.1, which may berelied upon and provide adequate support for specific embodiments withinthe scope of the appended claims.

The following examples are intended to illustrate the invention and arenot to be viewed in any way as limiting to the scope of the invention.

EXAMPLES

Bridged silicone resins in accordance with the present invention areprepared below. Before preparing the bridged silicone resins, certainbridging compounds are first prepared.

Preparation Example 1: Bridging Compound 1

A bridging compound (bridging compound 1) is produced via a Grignardreaction. In particular, 100 grams of p-dibromobenzene, 10 grams ofmagnesium, and 400 grams of diethylether are disposed in a flask to forma mixture. The mixture is heated to reflux, held at reflux for 6 hours,and then cooled to room temperature. 56.3 grams ofvinyldimethylchlorosilane are disposed into the flask and the contentsof the flask are stirred for 2 hours. Any volatiles are removed from theflask using a rotary evaporator to leave a concentrate. The concentrateis then purified by vacuum distillation to isolate the bridging compound1, which is 4-bis(vinyldimethylsilyl)benzene.

Preparation Example 2: Bridging Compound 2

A second bridging compound (bridging compound 2) is produced via aGrignard reaction. In particular, 100 grams of dibromophenoxy, 10 gramsof magnesium, and 400 grams of diethylether are combined in a flask toform a mixture. The mixture is heated to reflux, held at reflux for 12hours, and then cooled to room temperature. 40.5 grams ofvinyldimethylchlorosilane are added to the flask and the contents of theflask are stirred for 2 hours. Any volatiles are removed from the flaskusing a rotary evaporator to leave a concentrate. The concentrate isthen purified by vacuum distillation to isolate the bridging compound 2,which is 4-bis(vinyldimethylsilyl)phenoxybenzene.

Practical Example 1

A bridged silicone resin (bridged silicone resin 1) is produced inaccordance with the present invention.

Specifically, 100 grams of a hydrogen silsesquioxane resin (molecularweight of 12,000; 32.0% by weight in toluene), 3.2 grams of bridgingcompound 1, and 0.01 grams of Karsetedt's platinum (Pt) catalyst arecombined in a flask to form a mixture. The mixture is heated to refluxand stirred at reflux for 48 hours to form a silicone resin mixture. Thesilicone resin mixture is then cooled to 60° C., and 5 grams of activecarbon are disposed in the flask to form a suspension. The suspension isthen filtered and the filtrate is solvent exchanged with propyleneglycol monomethyl ether acetate (PGMEA) using a rotary evaporator to aform a 20% by weight in PGMEA solution of the bridged silicone resin 1.The bridged silicone resin 1 has the general formula(HSiO_(3/2))_(x)(SiO_(3/2)—CH₂CH₂—SiMe₂—C₆H₄—SiMe₂—CH₂CH₂—SiO_(3/2))_(y),where x is 0.979 , y is 0.021, and Me indicates a methyl group.

Practical Example 2

A bridged silicone resin (bridged silicone resin 2) is produced inaccordance with the present invention.

Specifically, 100 grams of a hydrogen silsesquioxane resin (molecularweight of 12,000; 32.0% by weight in toluene), 1.6 grams of bridgingcompound 1, and 0.01 grams of a platinum (Pt) catalyst are combined in aflask to form a mixture. The mixture is heated to reflux and stirred atreflux for 48 hours to form a silicone resin mixture. The silicone resinmixture is then cooled to 60° C., and 5 grams of active carbon aredisposed in the flask to form a suspension. The suspension is thenfiltered and the filtrate is solvent exchanged with propylene glycolmonomethyl ether acetate (PGMEA) using a rotary evaporator to a form a20% by weight in PGMEA solution of the bridged silicone resin 2. Thebridged silicone resin 2 has the general formula(HSiO_(3/2))_(x)(SiO_(3/2)—CH₂CH₂−SiMe₂—C₆H₄—SiMe₂—CH₂CH₂—SiO_(3/2))_(y),where x is 0.989, y is 0.011, and Me indicates a methyl group.

Practical Example 3

A bridged silicone resin (bridged silicone resin 3) is produced inaccordance with the present invention.

Specifically, 100 grams of a hydrogen silsesquioxane resin (molecularweight of 12,000; 32.0% by weight in toluene), 3.2 grams of bridgingcompound 2, and 0.01 grams of a platinum (Pt) catalyst are combined in aflask to form a mixture. The mixture is heated to reflux and stirred atreflux overnight to form a silicone resin mixture. The silicone resinmixture is then cooled to 60° C., and active carbon is disposed in theflask to form a suspension include 10 wt. % active carbon. Thesuspension is then filtered and the filtrate is solvent exchanged withpropylene glycol monomethyl ether acetate (PGMEA) using a rotaryevaporator to a form a 20% by weight in PGMEA solution of the bridgedsilicone resin 3. The bridged silicone resin 3 has the general formula(HSiO_(3/2))_(x)(SiO_(3/2)—CH₂CH₂—SiMe₂—C₆H₄—O—C₆H₄—SiMe₂—CH₂CH₂—SiO_(3/2))_(y),where x is 0.983, y is 0.017, and Me indicates a methyl group.

Practical Example 4

A bridged silicone resin (bridged silicone resin 4) is produced inaccordance with the present invention.

Specifically, 100 grams of a hydrogen silsesquioxane resin (molecularweight of 12,000; 32.2% by weight in toluene), 2 grams of bridgingcompound 3 (hydroxyl-terminated phenylmethyl organopolysiloxane, havingan average degree of polymerization (DP) of 4), and 0.2 grams of 4-ethylmorpholine are combined in a flask to form a mixture. The mixture isheated to 60° C. and stirred for 12 hours. 2.0 grams of acetic acid aredisposed in the flask to give a silicone resin mixture. The siliconeresin mixture is then washed with deionized water and solvent exchangedwith propylene glycol monomethyl ether acetate (PGMEA) using a rotaryevaporator to a form a 20% by weight in PGMEA solution of the bridgedsilicone resin 4. The bridged silicone resin 4 has the general formula(HSiO_(3/2))_(x)(SiO_(3/2)-(SiPhMeO)n-SiO_(3/2))_(y), where x is 0.992,y is 0.008, Me indicates a methyl group, Ph indicates a phenyl group,and n is 4.

Film Coating and Characterization

The PGMEA solutions of bridged silicone resins formed in PracticalExamples 1-4 may be utilized to form films on substrates, and inparticular on wafers. The particular PGMEA solution is filtered througha 0.2 millimeter (mm) TEFLON™ filter and then spin coated onto standardsingle side four inch polished low resistivity wafers or double sidedpolished Fourier Transform Infrared Spectroscopy (FTIR wafers via a KarlSuss CT62 spin coater, commercially available from SUSS MicroTec Inc. ofCorona, Calif.), to give a spinned film. The PGMEA solution andconcentration of bridged silicone resin therein, as well as the selectedrevolutions per minute of the spin coater, may be selected based ondesired thickness of the film. The spinned film is soft-baked at 180° C.for 60 seconds using a rapid thermal processing (RTP) oven with anitrogen gas purge to give a baked film. The baked film is then annealedat 350° C., 450° C., 550° C., 650° C., or 800° C. for 60 minutes undernitrogen to give the film. After the annealing, the wafer and film arecooled to room temperature and then inspected using optical microscopefor cracking. The thickness of the film is determined using a J. A.Woollam ellipsometer or a profilemeter, commercially available from J.A. Woollam Co. of Lincoln, Nebr.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. The invention may bepracticed otherwise than as specifically described.

1. A bridged silicone resin having the general formula (1): (HSiO_(3/2))_(x)(SiO_(3/2)—X—SiO_(3/2))_(y)  (1); wherein x and y are each from >0 to <1 such that x+y=1; and wherein X is divalent group comprising a silarylene group, or a —(CH₂)_(q)SiRR¹[O(SiRR¹O)_(n)]SiRR¹—(CH₂)_(q′)— group, where n is an integer from 1 to 10, each R and R¹ is an independently selected substituted or unsubstituted hydrocarbyl group, and q and q′ are each independently integers selected from 0 or from 1 to 6; and wherein each (HSiO_(3/2))_(x) group of the silicone resin has a weight average molecular weight of from 3,000 to 200,000 as determined by gel permeation chromatography (GPC) calibrated based on polystyrene standards.
 2. The bridged silicone resin of claim 1, wherein X has the general formula (2): (CH₂)_(q)—SiRR¹—X′—SiRR¹—(CH₂)_(q′)—  (2); wherein q and q′ are each independently selected and defined above; R and R¹ are independently selected and defined above; and X′ is a divalent linking group comprising an arylene group.
 3. The bridged silicone resin of claim 2, wherein X′ has the general formula (3):

wherein p is an integer selected from 0 or from 1 to 3, r is 0 or 1, k and each k′ are independently integers selected from 0 or from 1 to 4, Y and each Y′ are independently selected from N, O, and S, and each Z is independently selected from O, S, SiR² ₂, CO, CR² ₂, SO₂, PO₂ and NR², where each R² is independently H or a substituted or unsubstituted hydrocarbyl group.
 4. A method of preparing the bridged silicone resin of claim 1, said method comprising: reacting an initial silicone resin and a bridging compound to give the bridged silicone resin; wherein the initial silicone resin has a weight average molecular weight of from 1,500 to 100,000 as determined by GPC calibrated based on polystyrene standards and has the general formula (HSiO_(3/2))_(n′), where n′ is 1; and wherein the bridging compound has the general formula (4): R³—Z′—R³   (4); wherein each R³ independently is a functional group reactive with the silicon-bonded hydrogen atoms of the initial silicone resin, and Z′ comprises an arylene group or a siloxane moiety.
 5. The method of claim 4, wherein Z′ has the general formula (5): —SiRR¹—X′—SiRR¹—  (5); wherein each R and R¹ is independently selected and defined above; and X′ is a divalent linking group having the general formula (3):

wherein p is an integer selected from 0 or from 1 to 3, r is 0 or 1, k and each k′ are independently integers selected from 0 or from 1 to 4, Y and each Y′ are independently selected from N, O, and S, and each Z is independently selected from O, S, SiR² ₂, CO, CR² ₂, SO₂, PO₂ and NR², where each R² is independently H or a substituted or unsubstituted hydrocarbyl group.
 6. The method of claim 4, wherein reacting the initial silicone resin and the bridging compound comprises (i) a hydrosilylation reaction; (ii) a condensation reaction; or (iii) a combination of (i) and (ii).
 7. A method of forming a film with a bridged silicone resin, said method comprising: applying the bridged silicone resin to a substrate; and forming the film from the bridged silicone resin on the substrate; wherein the bridged silicone resin is the bridged silicone resin of claim
 1. 8. The method of claim 7, wherein the bridged silicone resin is applied by i) spin coating; ii) brush coating; iii) drop coating; iv) spray coating; v) dip coating; vi) roll coating; vii) flow coating; viii) slot coating; ix) gravure coating; or x) a combination of any of i) to ix).
 9. The method of claim 7, further comprising: spinning the silicone composition on the substrate to form a spinned layer on the substrate; and annealing the spinned layer to form the film on the substrate.
 10. A film formed in accordance with the method of claim
 7. 11. The film of claim 10 having a thickness of from greater than 0 to 10 micrometers.
 12. The film of claim 10 which substantially resists cracking when heated to a temperature of i) from 100 to 1000° C.; ii) from 400 to 850° C.; or iii) both i) and ii).
 13. An electronic device, comprising: an electronic component; and a film disposed adjacent the electronic component; wherein the film is the film of claim
 10. 14. (canceled)
 15. A method of insulating an electronic device which comprises an electronic component and a film disposed adjacent the electronic component, said method comprising: powering the electronic device such that the electronic component has an elevated temperature of from greater than 20° C. to 1,000° C.; wherein the film is the film of claim 10; and wherein the film insulates the electronic component and exhibits substantial resistance to cracking at the elevated temperature. 